When applying thermal spray coatings to the internal surfaces of axially split components such as fan casings, high energy thermal plasma spray techniques are commonly employed. During the coating processes, the high thermal energy and high coating application temperatures cause the residual stress in the coating and fan casing halves to distort. The resultant stress affects the quality and service life of the abradable coating. The thermal spray coating cracks and may spall or peel during use. As a result, cracked abradable coatings also affect the useful service life of the fan casing.
Therefore, there is a need for a process for applying a thermal spray coating upon an axially split component that reduces the stress experienced by the coating and component.